The embodiments described herein relate generally to aircraft landing gear systems and, more particularly, to electromechanical actuator systems used within aircraft landing gear systems.
At least some known electromechanical actuator systems include a housing that experiences varying pressures and temperatures during a typical flight cycle of an aircraft. For example, during the aircraft ascent, the internal pressure and temperature within the housing decreases as the external pressure and temperature of the surrounding environment decrease until the aircraft is at cruising altitude. Conversely, during the aircraft descent, the internal pressure and temperature within the housing generally increases as the external pressure and temperature of the surrounding environment increases.
At least some known electromechanical actuator systems balance the internal pressure and temperature within the housing with the external pressure and temperature of the surrounding environment by including an opening in the housing that facilitates venting of air into, and out of, the housing. For example, during aircraft ascent, the opening discharges air from the housing through the opening as the external pressure and temperature of the surrounding environment decreases. At cruising altitudes, the internal pressure and temperature within the housing are typically low enough that any liquid water within the housing may become frozen. During aircraft descent, air enters the housing through the opening as the external pressure and temperature of the surrounding environment increases. More specifically, when the landing gear bay doors open during landing, the warm, moist air may condense on an actuator mechanism encased within the housing when the actuator mechanism is still cold from the flight. Some condensation may be drawn into the actuator mechanism, and over time, such condensation may cause corrosion, hydrolysis, short circuits, and/or increase an overall mass of the actuator mechanism to the point wherein the actuator mechanism is inoperable.
To address the condensation problem, at least some known electromechanical actuator systems hermetically seal the actuator mechanism within the housing and use desiccants to facilitate reducing an amount of condensation that can accumulate over an extended period of time. However, sealing the actuator mechanisms within the housing causes a substantial pressure difference to be created between the internal pressure within the housing and the external pressure of the surrounding environment. The increased pressure difference may induce additional strain on the seals of the housing, which may cause premature failure of the seals over time.